On the observed changes in upper stratospheric and mesospheric temperatures from UARS HALOE

Abstract

Abstract. Temperature versus pressure or T (p) time series from the Halogen Occultation Experiment (HALOE) of the Upper Atmosphere Research Satellite (UARS) have been extended and re-analyzed for the period of 1991-2005 and for the upper stratosphere and mesosphere in 10-degree wide latitude zones from 60 S to 60 N. Even though sampling from a solar occultation experiment is somewhat limited, it is shown to be quite adequate for developing both the seasonal and longer-term variations in T (p). Multiple linear regression (MLR) techniques were used in the re-analyses for the seasonal and the significant interannual, solar cycle (SC-like or decadal-scale), and linear trend terms. Plots of the amplitudes and phases for the interannual (QBO and subbiennial) terms are provided. A simple SC-like term of 11-yr period was fitted to the time series residuals after accounting for the seasonal and interannual terms. Highly significant SC-like responses were found for both the upper mesosphere and the upper stratosphere. The phases of these SC-like terms were checked for their continuity with latitude and pressurealtitude; the larger amplitude responses are directly in-phase with that of standard proxies for the solar flux variations. The analyzed, max minus min, responses at low latitudes are of order 0.5 to 1 K, while at middle latitudes they are as large as 3 K in the upper mesosphere. Highly significant, linear cooling trends were found at middle latitudes of the middle to upper mesosphere (−1.5 to −2.0 K/decade), at tropical latitudes of the lower mesosphere (about −0.5 K/decade), and at 2 hPa (of order −1 K/decade). Both the diagnosed solar cycle responses and trends from HALOE for the mid to upper mesosphere at middle latitudes are larger than simulated with most models, perhaps an indication of decadal-scale dynamical forcings that are not being simulated so well.

Solar cycle response and long‐term trends in the mesospheric metal layers

“…The response of the MLT to both the 11 year solar cycle and longer‐term changes are not well known. Issues with data continuity, differences in spatiotemporal sampling, the choice of trend analysis employed, and the uncertainties associated with each measurement technique mean that trend studies are difficult and highly uncertain [e.g., see Remsberg , , ; Offermann et al ., ; Beig , ; Lübken et al ., ; Forbes et al ., ]. Within the MLT region, these considerations are particularly important due to the relatively limited number of observations available and the need to detect weak trends in what is typically geophysically variable data.…”

On the response of Halogen Occultation Experiment (HALOE) stratospheric ozone and temperature to the 11‐year solar cycle forcing

“…Section 3 includes the findings from those analyses and describes the important similarities and differences with the SC responses from the several other published, observed and modeled studies. Section 3 also relates the SC‐like responses from analyses of the HALOE temperature time series [ Remsberg and Deaver , 2005; Remsberg , 2007; Remsberg , 2008] and reviews how they compare with results from zonal‐mean models and observations. In general, reasonable agreement will be expressed for the model predictions of the SC responses in ozone and T(p) of Brasseur [1993] and Austin et al [2008] versus those found in the HALOE data.…”

Long-term trends observed in the middle atmosphere temperatures using ground based LIDARs and satellite borne measurements

“…Temperature trends derived from radiosonde data show stronger stratospheric cooling trends as compared to satellite measurements (Seidel et al, 2001;Lanzante et al, 2003a, b;Randel and Wu, 2006). By combining satellite, radiosonde and LIDAR observations Randel et al (2009) reported cooling trend of ∼ 0.5 K decade −1 in the lower stratosphere over much of the globe during the period 1979-2007. Temperature variability associated with the 11-year solar cycle, El Niño-Southern Oscillation (ENSO), and the QuasiBiennial Oscillation (QBO) has been found to be prominent in the lower and middle atmosphere, and plays a key role in the overall balance of its composition and circulation (Reid, 1994). The QBO is one of several possible "external" influences on the inter-annual variability of the northern stratospheric flow.…”

“…They revealed the dominance of the QBO (1-3 K) in the stratosphere and mesosphere, stronger winter signatures of ENSO in the troposphere and lower stratosphere (∼ 1.5 K/MEI), and maxima of solar cycle ∼ 1.3 K/100 F10.7 units at 35 and 55 km. A number of studies on the solar cycle influence on the temperature data have been carried out and reported (Clemesha et al, 1997;Sridharan et al, 2009;Keckhut et al, 2005;Remsberg and Deaver, 2005;Fadnavis and Beig, 2006;Remsberg, 2008;Beig, 2011b;Fadnavis et al, 2012). In addition, Li et al (2011) studied the long-term trend and solar cycle in the stratosphere and mesosphere using the long-term Rayleigh lidar temperature dataset at three different sites in the Northern Hemisphere.…”